(1) Field of the Invention
The present invention relates to electrotherapy and particularly to the electrical stimulation of controlled muscle activity. More specifically, this invention is directed to massage devices which may be employed to cause controlled muscle contractions. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.
(2) Description of the Prior Art
As employed herein the term "electrotherapy" relates to the direct application of electrical impulses to a living organism in the interest of achieving a therapeutic effect. As a science, electrotherapy has been know for many years. Apparatus employed for electrotherapy may be generally classified as nerve stimulators, which are generally intended to apply signals which interfere with the transmission of the sensation of pain to the brain, and muscle stimulators which are designed to cause controlled muscle contractions. In either case the object of electrotherapy is to stimulate the natural hearing and pain relief systems of the body when such systems are not functioning properly due to injury such as strains, sprains and bruises. In the case of muscle stimulation, the controlled contractions which are produced by the apparatus result in an increase in the flow of blood to and away from the damaged cells by alternately compressing and releasing the veins throughout the damaged area. This, of course, is what is accomplished by the alternate application of heat and cold and by massage, either manually or with apparatus such as an ultrasound transducer. The application of heat and cold is a very slow process whereas the various techniques for massage which are available generally require a great deal of expertise, particularly if the injury is not to be aggravated.
Examples of prior art electrical muscle stimulators may be seen in U.S. Pat. Nos. 2,641,259, 3,077,884, 4,114,893, 4,240,437, and 4,342,317. These examples of the prior art show the evolution of the apparatus which has been incident to the availability of solid state electronics, i.e., electrical muscle stimulators are rapidly becoming comparatively sophisticated devices considering the circuitry employed therein. However, as particularly evident from U.S. Pat. Nos. 4,144,893 and 4,240,437, the applicator portions of the devices have failed to evolve as rapidly as the electronics. Thus, in the prior art it is common to attach electrodes to the subject by means of belts or straps. This is often quite difficult to accomplish in the case of a four-legged animal. The need to use a belt or strap also impedes the ability to treat the subject in only a localized area. In many cases a single strapped-on electrode was used in conjuction with a hand-held applicator in the form of a rather cumbersome roller or the like which was inconveniently attached by a cable to a bulky combination signal generator and associated power supply.